The operation of human brain relies on processing different signals and data received from an outside environment by different sensory organs. Sources of the signals and data are mainly obtained via visual, auditory and kinesthetic senses. Thus these senses are critical for communication between people or between people and objects. Especially for children before school age, receiving external stimuli or signals via the auditory sense is of the same importance as that via the visual and kinesthetic senses. For example of learning speech, if a child is deaf and cannot successfully receive external sound signals, he or she fails to repeat the sound signals to learn speech. Moreover, loss of hearing for an adult also causes inconvenience in communication and may put this person in unconscious danger since humans usually rely on hearing to receive external sound signals and determine environmental changes. For example, a car accident may occur when a pedestrian who is hard of hearing is unable to receive the sound signals and notice a car coming behind.
In a medical aspect, hearing loss includes conductive hearing loss, sensory-neural hearing loss, mixed hearing loss and central hearing loss. Many hearing loss cases can be solved by internal medical methods, and most cases of conductive hearing loss can be treated through surgery. The sensory-neural hearing loss is usually screened during a child health examination to be diagnosed and treated in an early stage. Alternatively, a hearing aid device or various ways of language rehabilitation such as learning of lip language, oral language, sign language and auditory training so as not to impair the language development and learning of knowledge.
Therefore, For some of the hearing loss people especially those having the sensory-neural hearing loss, the hearing aid device is an essential auxiliary tool. The hearing aid device is actually a small loudspeaker, which amplifies the sound signals originally not detectable for the hearing loss people and transmits the amplified sound signals to a hearing center of the brain through the very weak hearing of the hearing loss people so as to allow them to receive the sound signals. An electronic hearing aid device has been used since early of the twenty century, and its basic structure including a microphone, an amplifier, a receiver and a power source always remains similar. However, the hearing aid device becomes reduced in the size of its component parts, and has gradually improved sound quality, as well as provides more control options. The microphone is to collect sounds and converts the collected sounds to voltage. The amplifier increases the voltage intensity. The receiver converts the increased voltage back to a sound wave. The power source supplies power for operating the hearing aid device. A housing is also provided for encapsulating and protecting the hearing aid device.
Although the foregoing hearing aid device can desirably allow some of the hearing loss people to receive the external sound signals, it functions simply to amplify the sound signals and clarify the amplified sounds, which may not be useful for all hearing loss people. Particularly, the hearing loss for the elders with increase in age is caused by aging of villi of hair cells in their inner ears by which the external sound signals are less likely to stimulate auditory nerves and to be perceived by the hearing center of the brain.
Once the villi became aged, the hearing loss people are not only unable to recognize soft sounds but also unable to recognize sounds with close sequential cues from extremely close words of fast speech. Furthermore, a tone level of a speaker also influences recognition by a listener especially for one who is hearing impaired. However, the currently available hearing aid devices do not relate to this problem nor solving it.
Therefore, the problem to be solved here is to provide a hearing aid device that can improve an auditory condition for hearing loss people according to causes of the hearing loss.